Merck’s Phase-III osteoporosis medication odanacatib showed that the weekly cathepsin K inhibitor significantly reduced the risk of osteoporotic hip, spine and non-vertebral fractures compared to placebo. Yet analysts think that Merck’s experimental oral may not be a major earner, despite results that include an impact that is in-line with biophosphonates.

Odanacatnib is also not associated with bone loss in the jaw, known as osteonecrosis, a side effect that has been associated with a series of osteoporosis medications including Merck’s biophosphonate Fosomax (alendronate) and Amgen’s Prolia (denosumab).

Despite a tepid investor response, Merck’s drug is of note because it is one the firm has repeatedly cited when highlighting pipeline items during earnings calls, along with the now-approved, and much-delayed sleep drug Belsomra (suvorexant).

Odanacatib patients did have a higher number of cardiovascular results, such as atrial fibrillation and stroke, compared to placebo, but analysts including ISI’s Mark Schoenebaum and Leerink’s Seamus Fernandez indicated in their Monday assessments that these differences were not insurmountable.

Merck is compiling more cardiovascular data, and the expectation is that the FDA will scrutinize it. Fernandez wrote that the result will probably be a drug approval with a safety warning. Jefferies analyst Jeffrey Holford projected in a Monday industry survey that the drug could have peak sales of around $2.5 billion.

Although odanacatib may not become a blockbuster, Amgen’s experience with the injection denosumab shows that an osteoporosis medication can be a steady earner. Branded as bone-strengthening Prolia for post-menopausal women, denosumab provided Amgen with $884 million in US sales between 2011 and 2013 and $1.4 billion worldwide for this same stretch. As Xgeva, which covers a series of indications related to bone metastases, denosumab earned Amgen close to $1.8 billion in US sales between 2011 and 2013 and $2.1 billion globally during this same period.